A simple, optimised and rapid assay for urinary free catecholamines by HPLC with electrochemical detection

A rapid method is described for the determination of urinary free catecholamines by HPLC with electrochemical detection. Optimised and equilibrium assay conditions are assessed for sample preparation, separation and detection. Catecholamine stability is maintained during the assay procedure by the addition of a combined reducing agent. Variability in recovery between aqueous standards and urine samples is minimised by dilution of samples with a concentrated Tris buffer solution. Ethyl acetate washing of an acid eluate is performed after and not before an alumina adsorption step in order to make the procedure as simple and rapid as possible. The method is evaluated and has thus far identified two cases of phaeochromocytoma and one case of neuroblastoma.